The role of glucagon-like peptide 1 receptor agonists for weight control in individuals with acquired hypothalamic obesity-A systematic review

Hypothalamic obesity does not respond well to conventional interventions for obesity. GLP-1 receptor agonists have mechanisms independent of the hypothalamus which may be potentially beneficial for managing hypothalamic obesity. This systematic review summarizes the efficacy and safety of GLP-1 receptor agonists use in hypothalamic obesity. A PRISMA-compliant systematic review was performed. Data was extracted from included studies and analysed based on change in weight, body mass index, glycaemic control, satiety, and safety profile with GLP-1 receptor agonist use. Ten studies comprising 5 case reports, 4 case series and 1 randomized-controlled trial included 54 patients (24 males, 30 females) with mean age of 25.2 (range 13-71) years with hypothalamic obesity who had received GLP-1 receptor agonists (exenatide = 48, liraglutide = 5 and dulaglutide = 1) over a mean duration of treatment of 12 (range 3-51) months. Mean weight reduction of 7.4 (SD 7.92) kg was observed in patients in whom weight was reported, with 85.7% of patients experiencing weight loss. All patients on liraglutide had weight reduction post-therapy. The sole trial had reported a non-significant reduction in BMI post-exenatide. Glycaemic control had either improved/maintained in all patients in whom this was measured. The main side effects of GLP-1 receptor agonist in individuals with hypothalamic obesity were nausea and vomiting; there were no major safety concerns. Based on limited published experience, GLP-1RA may be effective and safe for weight control in hypothalamic obesity, with the added benefit of improved glycaemic control in those with concurrent diabetes mellitus.

Screening for obstructive sleep apnea (OSA) in children and adolescents with obesity: A scoping review of national and international pediatric obesity and pediatric OSA management guidelines

Obstructive sleep apnea (OSA) is a prevalent complication that affects up to 60% of children and adolescents with obesity. It is associated with poorer cardiometabolic outcomes and neurocognitive deficits. Appropriate screening and intervention for OSA are crucial in the management of children with obesity. We performed a scoping review of international and national pediatric obesity (n = 30) and pediatric OSA (n = 10) management guidelines to evaluate the recommendations on OSA screening in pediatric obesity. Sixteen (53%) of the pediatric obesity guidelines had incorporated OSA screening to varying extents, with no consistent recommendations on when and how to screen for OSA, and subsequent management of OSA in children with obesity. We provide our recommendations that are based on the strength and certainty of evidence presented. These include a clinical-based screening for OSA in all children with body mass index (BMI) ≥ 85th percentile or those with rapid BMI gain (upward crossing of 2 BMI percentiles) and the use of overnight polysomnography to confirm the diagnosis of OSA in those with high clinical suspicion. We discuss further management of OSA unique to children with obesity. An appropriate screening strategy for OSA would facilitate timely intervention that has been shown to improve cardiometabolic and neurocognitive outcomes.

Quality of life and psychosocial outcomes among children with metabolically healthy and unhealthy obesity

BACKGROUND

Obesity and obesity-related morbidities are associated with poor psychosocial adjustment and health-related quality of life (HRQoL). This study aims to examine HRQoL and psychosocial outcomes in children with metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO), and the effects of familial health on these outcomes.

METHODS

Four hundred and six children with BMI for age ≥ 97th percentile were classified as having MHO and MUO based on the absence or presence of metabolic abnormalities. HRQoL and psychosocial outcomes were assessed using validated questionnaires such as PedsQL and DASS-21.

RESULTS

There were no significant differences in HRQoL and psychosocial outcomes between children with MHO and children with MUO. Children with MUO and prior knowledge of existing metabolic conditions reported significantly lower total HRQoL (71.18 ± 17.42 vs. 75.34 ± 15.33), and higher depression (12.16 ± 11.80 vs. 8.95 ± 8.52) and stress (12.11 ± 8.21 vs. 10.04 ± 7.92) compared to children with MHO. Children with MUO who had fathers with metabolically unhealthy phenotype reported significantly lower total HRQoL (72.41 ± 15.67 vs. 76.82 ± 14.91) compared to children with MUO who had fathers with metabolically healthy phenotype.

CONCLUSION

Prior knowledge of existing metabolic abnormalities was associated with poorer HRQoL and mental health in children with obesity. Paternal metabolic health status influenced HRQoL in children with MUO.

IMPACT

First study that compared health-related quality of life (HRQoL) and psychosocial outcomes between children with metabolically healthy obesity (MHO) and children with metabolically unhealthy obesity (MUO). No significant differences in HRQoL and psychosocial outcomes between children with metabolically healthy obesity (MHO) and children with metabolically unhealthy obesity (MUO). Children with MUO who had prior knowledge of existing metabolic conditions reported lower HRQoL, higher depression and stress compared to children with MHO. Paternal metabolic health status was found to influence HRQoL in children with MUO. Mental health support intervention with paternal involvement should be provided for children with MUO.

Screening for metabolic complications of childhood and adolescent obesity: A scoping review of national and international guidelines

The rise in prevalence of childhood obesity is paralleled by an increase in obesity-related metabolic complications, which add significantly to the population burden of cardiovascular morbidity in the long term. Early detection of obesity-related metabolic complications through appropriate screening strategies forms a crucial aspect of obesity management. We performed a scoping review of international and national guidelines on the management of pediatric obesity to evaluate the recommendations on screening for metabolic complications, namely, hypertension, diabetes, dyslipidemia, and non-alcoholic fatty liver disease. Thirty guidelines were included, 23 (76.7%) of which had some guidance on screening for metabolic complications. However, there were significant variations in the extent and details of recommendations for screening for these metabolic complications. There has been no consensus on the body mass index (BMI) thresholds, age of onset, frequency, and screening tests recommended for detecting hypertension, diabetes, dyslipidemia, and non-alcoholic fatty liver disease between guidelines. These variations did not appear to be polarized based on geographical location or population ethnicity. We provide our recommendations on metabolic screening based on the strength of evidence in the guidelines, also incorporating recommendations from key childhood hypertension, diabetes, and lipid guidelines. Appropriate implementation of screening strategies is crucial to improve detection of metabolic complications, to allow for earlier or more intensified interventions for affected children with obesity.

Physical Activity and Nutrition Interventions for Type 1 Diabetes: A Meta-analysis

BACKGROUND AND OBJECTIVES

Current evidence is lacking on physical activity and nutrition-based interventions focusing on the management of type 1 diabetes mellitus (T1DM) and health-related quality of life among children. To assess the effects of physical activity interventions and nutrition-based interventions for children with T1DM.

METHODS

Data sources include the Cochrane Central Register of Controlled Trials, Medline, clinicaltrials.gov, the World Health Organization International Clinical Trials Registry Platform, CINAHL through January 2022. Study selection includes randomized controlled trials of children aged 18 years and below with T1DM comparing either a physical activity intervention, a nutrition-based intervention, or hybrid physical activity and nutrition-based intervention with placebo or no-treatment control. Data were pooled using a random-effects model. Primary outcomes were hemoglobin A1c (HbA1c), and health-related quality of life.

RESULTS

Eighteen trials were included. Physical activity compared with the no-treatment group showed a lack of effect on HbA1c (mean difference = -0.58, 95% confidence interval -1.20 to 0.05; P value = .07). Nutrition-based intervention compared with no-treatment control for HbA1c level revealed a lack of effect (mean difference = -0.61, 95% confidence interval -1.48 to 0.26; P value = .17). Limitations include paucity of studies and low quality of evidence caused by the risk of bias.

CONCLUSIONS

Despite the lack of significant evidence, the generally favorable results highlight the potential of such interventions in enhancing glycemic control and health-related quality of life. Additionally, promising results from a single physical activity-nutrition-based hybrid intervention in terms of glycemic control indicate the plausible effectiveness of a mixed intervention.

Adherence and growth outcomes in children with growth disorders: results from the Easypod™ Connect Observational Study (ECOS) in Indonesia, Singapore, and Taiwan

Background Non-objective assessments indicate poor patient adherence to growth hormone (GH) prescribed for growth failure, with sub-optimal growth response. The easypod™ connect device for GH administration enables real-time, objective assessment of adherence. Objective To examine adherence with pediatric GH therapy in Asia-Pacific countries and relationship with growth outcomes. Methods Subjects were children in Indonesia, Singapore, Taiwan enrolled in the multi-national, open-label Easypod Connect Observational Study (ECOS). Adherence during follow-up was the primary endpoint and a relationship with 1-year growth outcomes was assessed by Spearman’s product-moment correlations. Results Over a 1-year time frame, median overall patient adherence was ≥89%; rates were similar for children with GH deficiency (GHD; n=17) and those born small-for-gestational age (SGA; n=5), except that median adherence dropped between 9 months (94%) and 1 year (83%) for SGA subjects. Median initial GH dose was 42.3µg/kg/day for GHD subjects and 31.4µg/kg/day for SGA subjects. Median age (12 years) and bone age (13 years) indicated that most children had entered puberty at treatment onset. Clinically meaningful improvements in growth were observed at 1 year in the GHD group, but not the SGA group. Statistically significant correlations between adherence and height change (P=0.039) as well as height velocity (P=0.004) were observed. Conclusions Children in Asia-Pacific countries show high adherence over the first year of GH therapy with easypod. The easypod study also shows that adherence is correlated to good growth outcomes.

The effects of glucagon-like peptide (GLP)-1 receptor agonists on weight and glycaemic control in Prader-Willi syndrome: A systematic review

OBJECTIVE

The mainstay management of hyperphagia and obesity in Prader-Willi syndrome (PWS) relies on dietary restrictions, strict supervision and behavioural modifications, which can be stressful for the patient and caregiver. There is no established pharmacological strategy to manage this aspect of PWS. Theoretically, glucagon-like peptide-1 (GLP-1) receptor agonists (GLP1-RA) used in patients with obesity and type 2 diabetes mellitus (T2DM) may be efficacious in weight and glycaemic control of PWS patients. We conducted a systematic review of the literature to summarize the evidence on the use of GLP1-RA in PWS patients.

DESIGN

Primary studies were searched in major databases using key concepts 'Prader-Willi syndrome' and 'GLP1 receptor agonist' and outcomes, 'weight control OR glycaemic control OR appetite regulation'.

RESULTS

Ten studies included, summarizing GLP1-RA use in 23 PWS patients (age, 13-37 years), who had used either exenatide (n = 14) or liraglutide (n = 9) over a duration of 14 weeks to 4 years. Sixteen (70%) of these patients had T2DM. Ten patients experienced improvement in body mass index, ranging from 1.5 to 16.0 kg/m² , while improvement in HbA1c was seen in 19 of 23 cases, ranging between 0.3% and 7.5%. All five studies reporting appetite or satiety showed improvement in satiety levels. There were no reported serious side effects.

CONCLUSIONS

GLP1-RA appears safe in PWS patients and may have potential benefits for weight, glycaemic and appetite control. Nonetheless, we also highlight a significant gap in the literature on the lack of well-designed studies in this area, which limits the recommendation of GLP1-RA use in PWS patients at present.

Association of leukocyte telomere length with obesity-related traits in Asian children with early-onset obesity

BACKGROUND

Leukocyte telomere length (LTL) is associated with obesity and obesity-related traits, and there are ethnic-specific determinants of LTL.

OBJECTIVE

To evaluate LTL associations with obesity and metabolic parameters in Asian children with early-onset obesity.

METHODS

Genomic DNA was extracted from peripheral blood leukocytes of a cohort of children with (N = 371) and without obesity (N = 23), and LTL was measured using quantitative PCR (qPCR). Blood plasma was used for metabolic phenotyping. Statistical analysis was performed using SPSS and STATA.

RESULTS

Children with obesity had shorter LTL (coefficient = -0.683, P_Adj = 1.24 × 10^-3 ) as compared to children who were lean. LTL was found to be associated with waist circumference (coefficient = -0.326, P_Adj = 0.044) and skin-fold measures (coefficient between 0.267 and 0.301, P_Adj between 4.27 × 10^-4 and 7.06 × 10^-7 ) in children with obesity. However, no significant associations were observed between LTL and metabolic parameters, and between LTL and inflammatory cytokines. LTL also did not significantly mediate the risk of non-alcoholic fatty liver disease (NAFLD) in children with obesity.

CONCLUSIONS

We showed for the first time that Asian children with severe obesity had shorter LTL, and the shortening of LTL was associated with other adiposity measures including waist circumference and skin-fold measurements.

Self and parent-proxy rated health-related quality of life (HRQoL) in youth with obesity: are parents good surrogates?

PURPOSE

Consideration of health-related quality of life (HRQoL) and wellbeing outcomes is important to guide healthcare services for youth with obesity, yet youth perspectives may differ from their parents. This study compared youth and parental HRQoL reports and evaluated levels of concordance across HRQoL domains and as a function of youth age, youth gender and parent informant (mother and father).

METHODS

376 youths with obesity, recruited from community (N = 223) and hospital settings (N = 153), and their parents (N = 190 mothers; N = 91 fathers), completed the PedsQL. Parental and youth agreement across subgroup dyads (mother; father; child gender; child age) were evaluated using Wilcoxon signed-rank test, intra-correlations coefficients (ICCs) and Bland-Altman plots.

RESULTS

Compared to norms, HRQoL levels (youth self-report and parental proxy reports) were lower in all domains. Both mother and fathers' HRQoL reports were significantly lower than youths, most notably in physical HRQoL. Youth-parent concordance ranged from poor to moderate (ICC = 0.230-0.618), with lowest agreement for Physical HRQOL. Mothers were better proxies with ICCs being significant in all domains. Youth-father ICCs were significant only for Social (ICC = 0.428) and School (ICC = 0.303) domains. Girl-mother agreement was significant across all domains, while girl-father agreement was significant only in the Social domain (ICC = 0.653). Both mothers and fathers were poor raters for boys, and younger youths (aged ≤ 12), with non-significant ICCs in most HRQoL domains.

CONCLUSIONS

Parents are poor surrogates for youth HRQoL. Clinicians should be cognizant that parents are not necessarily accurate proxies for youths, and exercise caution when interpreting parent-proxy scores.

Progression of Mineral Ion Abnormalities in Patients With Jansen Metaphyseal Chondrodysplasia

CONTEXT

Five different activating PTH/PTH-related peptide (PTHrP) receptor (PTHR1) mutations have been reported as causes of Jansen metaphyseal chondrodysplasia (JMC), a rare disorder characterized by severe growth plate abnormalities and PTH-independent hypercalcemia.

OBJECTIVES

Assess the natural history of clinical and laboratory findings in 24 patients with JMC and characterize the disease-causing mutant receptors in vitro.

PATIENTS AND METHODS

The H223R mutation occurred in 18 patients. T410P, I458R and I458K each occurred in single cases; T410R was present in a father and his two sons. Laboratory records were analyzed individually and in aggregate.

RESULTS

Postnatal calcium levels were normal in most patients, but elevated between 0.15 and 10 years (11.8 ± 1.37 mg/dL) and tended to normalize in adults (10.0 ± 1.03 mg/dL). Mean phosphate levels were at the lower end of the age-specific normal ranges. Urinary calcium/creatinine (mg/mg) were consistently elevated (children, 0.80 ± 0.40; adults, 0.28 ± 0.19). Adult heights were well below the 3rd percentile for all patients, except for those with the T410R mutation. Most patients with JMC had undergone orthopedic surgical procedures, most had nephrocalcinosis, and two had advanced chronic kidney disease. The five PTHR1 mutants showed varying degrees of constitutive and PTH-stimulated cAMP signaling activity when expressed in HEK293 reporter cells. The inverse agonist [L11,dW12,W23,Y36]PTHrP(7-36) reduced basal cAMP signaling for each PTHR1 mutant.

CONCLUSIONS

Except for T410R, the other PTHR1 mutations were associated with indistinguishable mineral ion abnormalities and cause similarly severe growth impairment. Hypercalciuria persisted into adulthood. An inverse agonist ligand effectively reduced in vitro PTH-independent cAMP formation at all five PTHR1 mutants, suggesting a potential path toward therapy.

In-vitro function of upstream visfatin polymorphisms that are associated with adverse cardiometabolic parameters in obese children

BACKGROUND

Visfatin is an adipokine associated with glucose and lipid metabolism. We previously reported two visfatin upstream single nucleotide polymorphisms (SNPs), c.-3187G > A (rs11977021) and c.-1537C > T (rs61330082), which were in perfect linkage disequilibrium, in a Singaporean cohort of severely obese children and are associated with visfatin level and adverse cardiometabolic parameters. We aim to functionally characterize the effect of c.-3187G > A and c.-1537C > T SNPs on basal transcriptional activity.

METHODS

A 1.6 kb and 3.7 kb upstream promoter region of the visfatin gene was amplified by polymerase chain reaction and separately cloned into luciferase reporter vectors. Successful clones were transfected into human embryonic kidney (HEK293T) and human breast carcinoma (MCF7) cells and in-vitro dual-luciferase assay was performed. Electrophoretic mobility shift assay (EMSA) was also conducted to examine the binding affinity between transcription factors and visfatin promoter sequences.

RESULTS

Variant promoter with only c.-1537C > T SNP did not show a change in transcriptional activity as compared to the wild type. However, variant promoter with both c.-3187G > A and c.-1537C > T SNPs showed a statistically significant increase of 1.41 fold (p < 0.01) in transcriptional activity. The longer 3.7kbp visfatin promoter sequence was also shown to have significantly higher transcriptional activity (p < 0.05) as compared to the shorter 1.6kbp visfatin promoter. Both c.-3187G > A and c.-1537C > T variants showed an increased binding with nuclear protein.

DISCUSSION AND CONCLUSIONS

We have demonstrated for the first time that visfatin variant promoter with both c.-3187G > A and c.-1537C > T SNPs result in an increase in transcriptional activity. This supports our previous finding and postulation that these SNPs contribute to elevated visfatin levels which may mediate higher triglyceride levels, severe systolic blood pressure and severe hypertension in obese children. These SNPs may co-operatively affect enhancer or silencer function to regulate transcriptional activity. In conclusion, this study shows that upstream visfatin SNPs could potentially affect phenotypic outcome in obese children through alteration of circulating visfatin level.

Exogenous Cushing syndrome: a lesson of diaper rash cream

A prolonged use of topical corticosteroids can result in Cushing syndrome, though this is less common than with oral or parenteral steroids. Most pediatric cases were due to application of topical steroids for diaper dermatitis. Adverse cardiovascular effects can occur in Cushing syndrome with significant long-term morbidity and mortality, though so far there have been no reports of cardiovascular complications due to excessive usage of topical steroids. We report a 2.5-month-old boy who rapidly developed severe Cushing syndrome induced by the misuse of topical clobetasol, a very potent steroid, without a doctor's prescription as a diaper rash cream, and developed moderate left ventricular hypertrophy and pericardial effusion.

Genetic Testing Confirmed the Early Diagnosis of X-Linked Hypophosphatemic Rickets in a 7-Month-Old Infant

Loss-of-function mutations in the phosphate regulating gene with homologies to endopeptidases on the X-chromosome (PHEX) have been causally associated with X-linked hypophosphatemic rickets (XLHR). The early diagnosis of XLHR in infants is challenging when it is based solely on clinical features and biochemical findings. We report a 7-month-old boy with a family history of hypophosphatemic rickets., who demonstrated early clinical evidence of rickets, although serial biochemical findings could not definitively confirm rickets. A sequencing assay targeting the PHEX gene was first performed on the mother’s DNA to screen for mutations in the 5′UTR, 22 coding exons, and the exon-intron junctions. Targeted mutation analysis and mRNA studies were subsequently performed on the boys’ DNA to investigate the pathogenicity of the identified mutation. Genetic screening of the PHEX gene revealed a novel mutation, c.1080-2A>C, at the splice acceptor site in intron 9. The detection of an aberrant mRNA transcript with skipped (loss of) exon 10 establishes its pathogenicity and confirms the diagnosis of XLHR in this infant. Genetic testing of the PHEX gene resulted in early diagnosis of XLHR, thus enabling initiation of therapy and prevention of progressive rachitic changes in the infant.

Functional characterization of variants in MC4R gene promoter region found in obese children

CONTEXT

Mutations in the MC4R gene are the most common cause of monogenic obesity, and there are few studies on mutations in the promoter region.

OBJECTIVE

The objective of the study was to sequence the promoter region of the MC4R gene in a cohort of obese children to identify rare variants.

DESIGN, SETTING, AND PATIENTS

A region 1500 bp upstream of the MC4R gene was sequenced in 267 unrelated local children younger than 10 years, with body weight of at least 150% of ideal. An 891-bp upstream region of the MC4R gene was cloned into a luciferase reporter vector for reporter gene assays.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

The basal transcriptional activity of the MC4R promoter was analyzed in human embryonic kidney 293 cells using reporter gene assays.

RESULTS

Three rare variants were detected: c.-803A>G, c.-105C>G, and c.-216C>T. The novel c.-803A>G variant was found in a 9-year-old severely obese Malay boy. This variant was not found in his severely obese mother but was present in his overweight father, who had type 2 diabetes, and also in his normal-weight brother. The novel c.-105C>G variant was found in an obese 9-year-old Malay boy. The c.-216C>T variant was found in an obese Chinese girl with Down's syndrome. The transcriptional activities of the c.-803A>G and c.-105C>G promoters were significantly reduced compared with the wild type but not the c.-216C>T promoter.

CONCLUSIONS

We have described, for the first time, two novel human MC4R gene promoter variants found in obese children that resulted in a decrease in basal transcriptional activity.

Visfatin and its genetic variants are associated with obesity-related morbidities and cardiometabolic risk in severely obese children

BACKGROUND

Visfatin is an adipokine, associated with obesity and possibly glucose regulation.

OBJECTIVE

The aim of this study was to examine the association of visfatin and its genetic variants with adiposity, cardiometabolic risk factors and obesity-related morbidities in obese children.

METHODS

Anthropometric measurements, dual energy X-ray absorptiometry scan, fasting blood samples and oral glucose tolerance tests were performed for 243 obese children. We screened the visfatin gene of 24 obese subjects and then performed genotyping of identified genetic variants in other 219 obese children through direct DNA sequencing.

RESULTS

Fasting serum visfatin correlated with measures of obesity and liver enzymes and was elevated in obese children with abnormal glucose tolerance and non-alcoholic fatty liver disease. The two upstream single nucleotide polymorphisms, -3187G>A (rs11977021) and -1537C>T (rs61330082), were at complete linkage disequilibrium. The AA genotype of -3187G>A was associated with higher serum visfatin (6.17 ± 0.76 ng mL(-1) vs. 3.92 ± 0.44 ng mL(-1)) and higher triglyceride (1.39 ± 0.08 mmol L(-1) vs. 1.19 ± 0.07 mmol L(-1)) as compared with the GG genotype. There was also a significant linear increase in serum visfatin across GG to GA to AA genotype of -3187G>A, indicating possible additive effect of A allele. The dominant GA + AA genotype model of +21426G>A (rs2302559) was associated with lower serum visfatin (3.83 ± 0.56 ng mL(-1) vs. 5.13 ± 0.34 ng mL(-1)) and lower plasma glucose (4.37 ± 0.08 mmol L(-1) vs. 4.77 ± 0.12 mmol L(-1)) as compared with the GG genotype.

CONCLUSION

Visfatin and its genetic variants were associated with adiposity, obesity-related morbidities and adverse cardiometabolic parameters. This supported our hypothesis that visfatin plays a significant role in the development of obesity-related morbidities and cardiometabolic risk.

Spuriously elevated free thyroxine associated with autoantibodies, a result of laboratory methodology: case report and literature review

OBJECTIVE

We describe a case of spurious hyperthyroxinemia secondary to thyroid hormone autoantibodies (THAAbs) in a clinically euthyroid patient with Turner mosaic syndrome.

METHODS

Several commonly available laboratory-based approaches were used, which indicated a disproportionate elevation of free thyroxine (T4) and ultimately led to the diagnosis of THAAbs. A literature review was undertaken to examine the clinical and laboratory associations of THAAbs.

RESULTS

The free T4 result of the patient was highly discrepant when measured using an Advia Centaur platform (5.89 ng/dL) as compared with the Vitros 5600 and DxI 800 platforms (1.03 and 0.74 ng/dL, respectively). Polyethylene glycol precipitation of the patient's sample showed reduced free T4 recovery (26%), suggesting the presence of a high-molecular-weight interfering substance. Rheumatoid factor and heterophile blocking tube studies were negative. These results suggested a presumptive diagnosis of THAAbs. Direct detection of THAAbs using a radiobinding method confirmed the diagnosis. A review of the literature showed that THAAbs are prevalent among patients with (autoimmune and nonautoimmune) thyroid disorders and nonthyroid autoimmune disorders but rarely cause spurious measurements. Possible pathogenesis includes molecular mimicry, exposure of the antigenic surfaces of iodinated thyroglobulin molecules to B lymphocytes in injurious or inflammatory conditions involving the thyroid gland. Free thyroid hormone methods using one-step analog and labeled antibody designs are prone to falsely high measurements, whereas two-step analog designs may produce spuriously low results.

CONCLUSION

THAAbs are an underrecognized cause of laboratory interference that is best approached by joint clinical-laboratory efforts. The routine laboratory techniques described above can suggest preliminary diagnosis of this rare entity.

Familial male-limited precocious puberty in neurofibromatosis type I

Precocious puberty in patients with neurofibromatosis type 1 (NF-1) is predominantly central in origin, with intracranial pathologies like optic glioma. We describe one patient with NF-1 who presented with precocious puberty with the eventual diagnosis of familial male-limited precocious puberty and share the potential pitfalls. He presented at 7 years of age with growth spurt and pubertal genitalia development with enlarged testicular volume of 7 mL, but LHRH stimulation test revealed blunted luteinizing hormone and follicle-stimulating hormone peak suggestive of a peripheral cause, contrary to the expectation due to the background of NF-1. Testosterone level was elevated with bone age advancement by 2 years. Genetic analysis revealed a previously reported heterozygous missense mutation of the luteinizing hormone/choriogonadotropin receptor gene Ala572Val. His father was also heterozygous for the same mutation but was apparently asymptomatic and not short.

CONCLUSION

Our report illustrates two potential pitfalls in the clinical evaluation of patients with familial male-limited precocious puberty (FMPP). Firstly, patients with FMPP will have mild to moderately enlarged testes and should not be wrongly diagnosed as central precocious puberty without the gonadotropin-releasing hormone stimulation test. Secondly, family members with the same mutation may have different phenotypic severities, where some male carriers may have subtle features.

The association of a nucleobindin 2 gene (NUCB2) variant with childhood adiposity

Nucleobindin 2 (NUCB2) is a precursor of nesfatin-1, a hypothalamic anorectic neuropeptide. The association between variants of the NUCB2 gene and adiposity was examined. 142 severely obese Chinese children in Singapore, and 384 normal weight Chinese children from a longitudinal cohort from Da Qing, China, were studied. NUCB2 was screened using PCR and direct sequencing in 29 severely obese children and 24 non-obese children, then screened for a variant c.1012C>G (Q338E, or rs757081) in the rest of the cohort using TaqMan probe. Five variants, including c.1012C>G (Q338E) were found. Genotyping for c.1012C>G found that the GG genotype was significantly less frequent in the obese group; odds ratio for obese subjects carrying the CC and CG genotypes was 2.29 (95% CI 1.17-4.49) in the dominant model, CC genotype 2.86 (95% CI 1.41-5.81) in the additive model, and C allele 1.57 (95% CI 1.17-2.1). The findings were replicated in an independent cohort of 372 obese and 390 normal weight Chinese children, where the odds ratio of obese subjects with CC and CG genotypes was 1.69 (95% CI 1.12-2.55). Within the Da Qing cohort, subjects with the GG genotype had significantly lower BMI and percentage ideal weight for height (WFH) at 5 and 8years of age. Subjects with lower birth weights also had more pronounced difference in WFH and BMI at 5 and 10years of age between GG subjects versus CC/CG subjects. We postulate that GG genotype is protective against excessive weight gain, and factors which predispose to excessive weight gain such as higher birth weights may ameliorate the effect.

Normative Data for Quantitative Calcaneal Ultrasound in Asian Children

Introduction: Dual energy X-ray absorptiometry (DEXA) is currently the gold standard for the assessment of bone mineral density. Quantitative ultrasound (QUS), on the other hand, is a radiation-free alternative for the assessment of bone strength in the paediatric population. Establishing normative data for bone strength specific to the population would allow identification of children at risk of osteoporosis as a consequence of disease and its treatment. This cross-sectional study aims to establish the normal reference range for calcaneal broadband ultrasound attenuation (BUA) measurements in normal Singaporean children aged 6 to 12 years. Materials and Methods: Healthy Singaporean children were randomly selected from 11 primary schools for the assessment of calcaneal BUA, using the paediatric Contact Ultrasonic Bone Analyzer (CUBA, McCue Plc, Compton, Winchester, England). The height, weight, body mass index and BUA measurements for each age group and gender were expressed as the mean ± SD. One-way ANOVA was used to compare the mean calcaneal BUA by age and gender of Singaporean children with that of children from the United Kingdom, Turkey and Taiwan. Results: A total of 750 healthy Singaporean children (417 males and 333 females) aged 6 to 12 years from 11 primary schools were enrolled. The calcaneal BUA values of Turkish and white British children were not statistically different from this Singaporean cohort. However, the Singaporean calcaneal BUA measurements were significantly higher compared to the Taiwanese children. Conclusion: This study provides the first normal reference data to evaluate bone strength in Singaporean children using the paediatric Contact Ultrasonic Bone Analyzer. Keywords: Bone strength, Osteoporosis, Paediatrics

Normative data for quantitative calcaneal ultrasound in Asian children

INTRODUCTION

Dual energy X-ray absorptiometry (DEXA) is currently the gold standard for the assessment of bone mineral density. Quantitative ultrasound (QUS), on the other hand, is a radiation-free alternative for the assessment of bone strength in the paediatric population. Establishing normative data for bone strength specific to the population would allow identification of children at risk of osteoporosis as a consequence of disease and its treatment. This cross-sectional study aims to establish the normal reference range for calcaneal broadband ultrasound attenuation (BUA) measurements in normal Singaporean children aged 6 to 12 years.

MATERIALS AND METHODS

Healthy Singaporean children were randomly selected from 11 primary schools for the assessment of calcaneal BUA, using the paediatric Contact Ultrasonic Bone Analyzer (CUBA, McCue Plc, Compton, Winchester, England). The height, weight, body mass index and BUA measurements for each age group and gender were expressed as the mean ± SD. One-way ANOVA was used to compare the mean calcaneal BUA by age and gender of Singaporean children with that of children from the United Kingdom, Turkey and Taiwan.

RESULTS

A total of 750 healthy Singaporean children (417 males and 333 females) aged 6 to 12 years from 11 primary schools were enrolled. The calcaneal BUA values of Turkish and white British children were not statistically different from this Singaporean cohort. However, the Singaporean calcaneal BUA measurements were significantly higher compared to the Taiwanese children.

CONCLUSION

This study provides the first normal reference data to evaluate bone strength in Singaporean children using the paediatric Contact Ultrasonic Bone Analyzer.

Diagnostic Accuracy of Anthropometric Indices for Obesity Screening Among Asian Adolescents

Introduction: Weight-and-height-based anthropometric indices have long been used for obesity screening among adolescents.However, the ability of their age-and-sex-specific reference values in classifying adolescent as “obese” in different populations was not fully established. Our study aimed to validate the existing international (BMI-for-age charts from WHO, CDC, IOTF) and local cut-offs [percent weight for height (PWH)] for obesity against body fat percentage, as assessed by 4 skinfolds measurement. Materials and Methods: A cross-sectional sample of 6991 adolescents aged 12 to 18 years was measured. All anthropometric measurements were compliant with the internationally accepted protocol. Obesity was defined as percentage body fat greater than or equal to 95 percentile, specific to age and sex. The validity of the existing classification criteria in detecting obesity was evaluated by comparing their respective diagnostic accuracy. Results: Both prevalence of obesity and diagnostic accuracy indices varied by the classification criteria. While all criteria generated very high specificity rates with the lowest being 95%, their sensitivity rates were low ranging from 43% to 71%. Youden’s index suggested that CDC and WHO criteria had optimal sensitivity and specificity. ROC analysis showed that overall performance could be improved by refining the existing cut-offs. Conclusions: Clinical validity of weight-and-height-based classification systems for obesity screening in Asian adolescents is poorer than expected, and this could be improved by refining the existing cut-offs. Key words: BMI-for-age references, Percentage body fat, Singapore, Validity, Weight-for height

Diagnostic accuracy of anthropometric indices for obesity screening among Asian adolescents

INTRODUCTION

Weight-and-height-based anthropometric indices have long been used for obesity screening among adolescents.However, the ability of their age-and-sex-specific reference values in classifying adolescent as "obese" in different populations was not fully established. Our study aimed to validate the existing international (BMI-for-age charts from WHO, CDC, IOTF) and local cut-offs [percent weight for height (PWH)] for obesity against body fat percentage, as assessed by 4 skinfolds measurement.

MATERIALS AND METHODS

A cross-sectional sample of 6991 adolescents aged 12 to 18 years was measured. All anthropometric measurements were compliant with the internationally accepted protocol. Obesity was defined as percentage body fat greater than or equal to 95 percentile, specific to age and sex. The validity of the existing classification criteria in detecting obesity was evaluated by comparing their respective diagnostic accuracy.

RESULTS

Both prevalence of obesity and diagnostic accuracy indices varied by the classification criteria. While all criteria generated very high specificity rates with the lowest being 95%, their sensitivity rates were low ranging from 43% to 71%. Youden's index suggested that CDC and WHO criteria had optimal sensitivity and specificity. ROC analysis showed that overall performance could be improved by refining the existing cut-offs.

CONCLUSIONS

Clinical validity of weight-and-height-based classification systems for obesity screening in Asian adolescents is poorer than expected, and this could be improved by refining the existing cut-offs.

Clinical applications of molecular genetics: the model of congenital adrenal hyperplasia

Spectacular advances in molecular genetics have enabled the molecular characterisation of many genetic disorders. The clinical applications include: (i) identification of pre-symptomatic and symptomatic affected individuals (monogenic diseases), allowing for early treatment and prevention of complications, (ii) carrier testing for genetic counselling, (iii) pharmacogenetic testing to guide medical treatment, and (iv) susceptibility testing (in polygenic diseases) to determine the risk of developing future disease. Using the model of congenital adrenal hyperplasia (CAH), direct mutational analysis can be applied to: (i) confirm the diagnosis when hormone assays have been equivocal, which would allow for early treatment and prevention of adrenal crisis, (ii) prenatal diagnosis and prenatal treatment in affected females to prevent or reduce prenatal virilisation, (iii) heterozygote carrier identification for genetic counselling, (iv) novel therapeutic applications to optimise treatment, including adjusting the steroid dose based on consistent genotype-phenotype correlations, so as to reduce the incidence of growth-inhibiting effects of steroid excess. However, molecular analysis can occasionally be complicated by multiple mutations on one allele, which may potentially affect genotype-phenotype correlations. Hence, molecular genetic analysis of CAH may eventually be adopted as a second tier confirmation of the disease, but is unlikely to replace the current first tier screening assays of precursor steroid metabolites proximal to the enzyme deficiency.

3rd College of Paediatrics and Child Health Lecture – The Past, the Present and the Shape of Things to Come…

The growth trends of Singapore children spanning 5 decades are reviewed, based on 8 anthropometric studies from 1957 till 2002. The heights of pre-school children and school age children appear to have optimised according to their genetic potential, but the weights and body mass indices of children still appear to be increasing from 6 to 18 years for both sexes, probably as a consequence of increasing affluence. This trend is reflected in the increasing obesity prevalence in school children over the past 30 years, and the concomitant increased morbidity associated with the metabolic syndrome, necessitates further research into the causes of obesity. Barker’s hypothesis first suggested that changes in the intra-uterine environment can cause fetal adaptations which persist into adulthood, and are responsible for many chronic diseases of adult life. More recently, intense research in the field of epigenetics suggests that the environment can also influence the phenotype through gene expression, through modification of DNA methylation and histones which, in turn, influences gene expression. The challenge for the future is to determine if there are clear epigenetic changes, which are responsible for the increased prevalence of childhood and adolescent obesity, and whether these changes are transmitted through generations. Unravelling these epigenetic mechanisms may be the key to the prevention of obesity and the metabolic syndrome. Key words: Body mass index, Epigenetics, Height, Weight

3rd College of paediatrics and child health lecture--the past, the present and the shape of things to come

The growth trends of Singapore children spanning 5 decades are reviewed, based on 8 anthropometric studies from 1957 till 2002. The heights of pre-school children and school age children appear to have optimised according to their genetic potential, but the weights and body mass indices of children still appear to be increasing from 6 to 18 years for both sexes, probably as a consequence of increasing affluence. This trend is reflected in the increasing obesity prevalence in school children over the past 30 years, and the concomitant increased morbidity associated with the metabolic syndrome, necessitates further research into the causes of obesity. Barker's hypothesis first suggested that changes in the intra-uterine environment can cause fetal adaptations which persist into adulthood, and are responsible for many chronic diseases of adult life. More recently, intense research in the field of epigenetics suggests that the environment can also influence the phenotype through gene expression, through modification of DNA methylation and histones which, in turn, influences gene expression. The challenge for the future is to determine if there are clear epigenetic changes, which are responsible for the increased prevalence of childhood and adolescent obesity, and whether these changes are transmitted through generations. Unravelling these epigenetic mechanisms may be the key to the prevention of obesity and the metabolic syndrome.

Gonadal mosaicism 45,X/46,X,psu dic(Y)(q11.2) resulting in a Turner phenotype with mixed gonadal dysgenesis

A two-year-and-eight-month-old girl presented with clitoromegaly and short stature. Two cell lines, 45,X and 46,X,idic(Y)(q11.2), were observed. Cytogenetic and fluorescence in situ hybridisation investigations were carried out on her peripheral lymphocytes and gonadal cells, to determine the genotype-phenotype effect with respect to differential tissue distribution, effects of the sex determining region of the Y chromosome, and the break-points in the azoospermia factor region.

Novel melanocortin 4 receptor gene mutations in severely obese children

OBJECTIVE

Melanocortin 4 receptor (MC4R) deficiency is the commonest monogenic form of obesity. The significance of MC4R mutations in Asian obese populations has not been adequately examined. The objective of this study was to determine the role of MC4R mutations in severely obese Asian children.

DESIGN

We screened 227 obese local children and adolescents for MC4R gene mutations by polymerase chain reaction and direct sequencing.

RESULTS

We identified three mutations in three subjects: 4 bp deletion from nucleotides 631-634 (c.631-634delCTCT), Tyr157Ser (c.470 A > C) and 1 bp deletion at nucleotide 976 (c.976delT) (1.32% of study subjects). The latter two mutations are novel. The Tyr157Ser mutation was not found in 188 non-obese controls using restriction enzyme digest analysis. In vitro transient transfection studies supported the pathogenic role of both novel mutations Tyr157Ser and c.976delT, where the signalling activities of the mutant receptors were impaired. Heterozygous MC4R mutations were associated with early-onset severe obesity, and homozygosity of the MC4R mutation Tyr157Ser resulted in morbid obesity.

CONCLUSION

MC4R mutations result in an autosomal codominant form of obesity with variable expressivity. MC4R deficiency is not as common among the obese children in this study compared to other populations. Family studies revealed that adults heterozygous for the mutations were less obese compared to the children. We hypothesize that this may be due to amelioration of phenotype severity with age, genetic anticipation or difference in exposure to modifying factors at critical stages of childhood such as the environment.

The role of melanocortin 3 receptor gene in childhood obesity

OBJECTIVE

Melanocortin 3 receptor (MC3R) plays a critical role in weight regulation of rodents, but its role in humans remains unclear. The objective of this study was to identify genetic variants of the MC3R gene and determine its association with childhood obesity.

RESEARCH DESIGN AND METHODS

We screened 201 obese children for MC3R gene mutations with anthropometric measurements, blood tests, feeding behavior, and body composition assessment. We identified three novel heterozygous mutations (Ile183Asn, Ala70Thr, and Met134Ile) in three unrelated subjects, which were not found in 188 control subjects, and two common polymorphisms Thr6Lys and Val81Ile.

RESULTS

In vitro functional studies of the resultant mutant receptors revealed impaired signaling activity but normal ligand binding and cell surface expression. The heterozygotes demonstrated higher leptin levels and adiposity and less hunger compared with obese control subjects, reminiscent of the MC3R knockout mice. Family studies showed that these mutations may be associated with childhood or early-onset obesity. The common variants Thr6Lys and Val81Ile were in complete linkage disequilibrium, and in vitro studies revealed reduced signaling activity compared with wild-type MC3R. Obese subjects with the 6Lys/81Ile haplotype had significantly higher leptin levels, percentage body fat, and insulin sensitivity, and the causative role of the 6Lys/81Ile variants is supported by the presence of an additive effect in which heterozygotes had an intermediate phenotype compared with homozygotes.

CONCLUSIONS

MC3R mutations may not result in autosomal dominant forms of obesity but may contribute as a predisposing factor to childhood obesity and exert an effect on the human phenotype. Our report supports the role of MC3R in human weight regulation.

Detection through screening of maternal thyrotoxicosis induced central hypothyroidism in newborns

Use of a third generation TSH assay enabled extremely low values of TSH to be detected through newborn screening. The use of a supplemental free thyroxine improved testing specificity. The hypothyroidism observed is believed to be secondary to suppression of the hypothalamic-pituitary-thyroid axis by placentally transferred maternal thyroxine.

The perils of puberty

Puberty and adolescence represent a transitional phase from childhood to adulthood, and are defined by the attainment of secondary sexual characteristics and reproductive capability, occurring concomitantly with psychological and social development. The perils of puberty lie in the difficult and complex inter-relationship of biological, psychological and social changes, as the adolescent strives to adjust to new social roles and identities, and new reproductive capacities. An appreciation of these changes in normal puberty is essential to all professionals caring for adolescents.

Evidence of autoantibodies to glutamic acid decarboxylase in oral fluid of type 1 diabetic patients

Circulating antibodies to glutamic acid decarboxylase (GADab) are a major indicator for autoimmune destruction of pancreatic islet cells (type 1 diabetes). Previously reported detection of GADab in oral fluid, however, was assayed by enzyme-linked immunosorbent assay (ELISA) with low diagnostic sensitivity and high non-specific binding. We re-assessed oral fluid GADab detection using a different sampling technique and a more robust assay. Type 1 diabetic subjects (n = 32; mean age +/- SD: 13.9 +/- 3.7 years) provided Orasure oral fluid and venous blood samples. Orasure collections were assayed for total immunoglobulin G (IgG), then concentrated to 1/10 of their volume using mini-centrifugal protein concentrators. All samples were assayed by a GAD65 antibody radio-immunoprecipitation method. Oral fluid antibodies were detected ( > 99th percentile of radio-binding (%counts per min (%cpm)) for seronegatives) in 10/16 seropositive subjects, with %cpm (median: 6.4%; range: 4.6-25.8) significantly greater (P < 0.001) than for seronegatives (median: 4.7%; range: 3.4-5.7). A highly significant correlation (Spearman's rho: 0.85; P<0.001) was demonstrated between %cpm of concentrates and respective serum titres for seropositive diabetics. Median IgG concentration of Orasure collections was 22.8 mg/l (range: 9.4-168.0). GADab recovery from Orasure collectors was estimated at 90%. This is the first confirmatory detection of diabetes-specific autoimmune markers in oral fluid. Acceptable correlation between concentrated oral fluid radio-binding and serum titre was achieved. Improved antibody recovery and assay re-optimisation could provide a basis for more extensive studies that may lead to an alternative non-invasive screening method for pre-clinical autoimmune diabetes.

Maternal thyrotoxicosis causing central hypothyroidism in infants

We describe three infants born to mothers with poorly controlled Graves' disease, who developed transient central hypothyroidism in the immediate postnatal period. Suppression of the fetal pituitary-thyroid axis may be due to placental transfer of thyroxine from the hyperthyroid mother. This may persist for months postnatally, necessitating treatment to optimise neurodevelopmental outcome.

Epidemiology of 21-hydroxylase deficiency in Singapore

We report the incidence and epidemiology of 21-hydroxylase deficiency in Singapore, based on a retrospective study of all known patients diagnosed with classical 21-hydroxylase deficiency in the past 21 years. The database was obtained from the case registry and questionnaire methodology, with 100% coverage of all practising pediatricians in Singapore. There were 42 patients affected with 21-hydroxylase deficiency in 964,558 live births over 21 years, comprising 64.3% salt wasters and 35.7% simple virilizers, of whom 50.0% were males and 50.0% females. The incidence of classical 21-hydroxylase deficiency is 4.5 per 100,000 live births, with a carrier frequency of 1:76, and a gene frequency of 0.0067. Although retrospective studies have inherent limitations, the gender and phenotype ratios suggest that the data provide a crude incidence level. This study underscores the necessity for prospective neonatal screening, so that the benefits of early diagnosis and treatment can be realized.

Tyrosine phosphatase-like protein (IA-2) and glutamic acid decarboxylase (GAD65) autoantibodies: a study of Chinese patients with diabetes mellitus

Type 1 diabetes in most Asian populations may not have a salient autoimmune basis when assessed with single determinations of the major markers, islet cell antibodies (ICAs) and glutamic acid decarboxylase antibodies (GAD65ab). With the inclusion of antibodies to tyrosine phosphatase-like protein IA-2 (IA-2ab) as an additional major marker, we re-examined autoimmune diabetes in a group of Chinese patients. We studied 272 subjects at various stages of disease with blood samples procured for biochemical analysis. ICAs were measured by immunofluorescence, GAD65ab and IA-2ab by radioimmunoassay. Sixty-seven patients fulfilled clinical diagnosis of type 1 diabetes and the remaining 205 patients were type 2. Prevalence of single autoantibody type in recent-onset type 1 diabetes ( < 1 year duration; n = 47) showed 10.6% with ICAs, 44.7% GAD65ab and 36.2% IA-2ab. GAD65ab account for more than two-thirds of the markers found in type 1 diabetes. Combined analysis further showed that 51.1% had at least one antibody type, 31.9% with two or more antibodies and 8.5% with all three antibodies. Islet autoimmunity presence in childhood-onset type 1 diabetes improved with the addition of IA-2ab, though less impact was seen in the adult-onset. Similarly, combined analysis for type 2 patients with recent diabetes showed a modest increase to 13% with islet autoimmunity compared to 8% when assessed by GAD65ab alone. Combining IA-2ab and GAD65ab assays results detected slightly more immune-mediated diabetes, compared to using a single GAD65ab determination. Non-autoimmune causes need to be considered in the pathogenesis of type 1 diabetes in Chinese, particularly in adults.

Molecular analysis of CYP-21 mutations for congenital adrenal hyperplasia in Singapore

BACKGROUND

Congenital adrenal hyperplasia arising from 21-hydroxylase deficiency is associated with mutations in the CYP21 gene on chromosome 6p. This is the first report on the mutational spectrum of the CYP21 gene in Singapore.

METHODS

To catalogue the mutations, ten exons of the CYP21 gene from 28 Singaporean patients were analyzed by PCR amplification and direct sequencing.

RESULTS

Common mutations in descending order were the intron 2 splice site mutation (32.7% of the alleles), the I172N mutation (23.1% of the alleles), and the R356W mutation (19.2% of the alleles). Two potentially novel mutations were discovered: (1) duplication of 111 bp from codon 21 to codon 57 (exon 1) and (2) missense mutation (L261P, exon 7). There was generally a good genotype-phenotype correlation, allowing accurate prediction of the disease severity.

Cyclic pamidronate infusion improves bone mineralisation and reduces fracture incidence in osteogenesis imperfecta

A prospective open study was performed to determine the efficacy and safety of pamidronate in improving bone mineralisation and reducing fracture incidence in osteogenesis imperfecta (OI). Intravenous pamidronate was administered at 1.5 mg/kg bi-monthly to six children with OI, over 12-23 months. The number of fractures decreased from median of 3 (range 1-12) to 0 fractures/year (range 0-4) (P<0.05). After 12 months of treatment, there was significant improvement in areal bone mineral density (BMD) z-scores of the lumbar spine from median of -2.40 (range -3.20 to -1.67) to -1.90 (range -2.38 to -0.91) (P<0.05) and in the volumetric BMD which increased from median of 0.095 to 0.146 g/cm3 (P<0.05). Urine N-telopeptide levels (bone resorption marker) decreased from a median of 461.5 bone collagen equivalent/creatinine (BCE/Cr) (range 129-721 BCE/Cr) to 223.5 BCE/Cr (range 107-312 BCE/Cr) (P<0.05) and serum alkaline phosphatase (ALP) (bone formation marker) from a median of 230.0 U/l (range 148-305 U/l) to 133.5 U/l (range 79-233 U/l) (P<0.05), reflecting reduced bone turnover. This may represent a net reduction in bone resorption and provides a biochemical explanation for the increase in bone mineralisation. Height standard deviation scores were not affected and there were no significant adverse effects.

CONCLUSION

1 year cyclical pamidronate is effective and safe in improving bone mineralisation and reducing fracture incidence in osteogenesis imperfecta.

Mitochondrial tubulopathy: the many faces of mitochondrial disorders

We report a rare presentation of mitochondrial disorder in a child with recurrent carpopedal spasms due to hypocalcemia and hypomagnesemia, secondary to renal proximal tubulopathy and possible hypoparathyroidism. At least two mutant mitochondrial DNA species were identified, and abnormal mitochondria were found in the muscle and renal biopsy specimens. The case illustrates the spectrum and diversity of mitochondrial presentations, arising because of heteroplasmy of mutations and the type of organs affected.